736 DISEASES OF THE CUTANEOUS SYSTEM. 



system generally, which attaches to them in man, are yet 

 from various considerations deserving of more attention than 

 has generally been bestowed upon them. 



Ever since any care or special knowledge has been directed 

 to the consideration of animal diseases, the larger proportion 

 of cutaneous affections have, in the gross, been looked upon 

 as manifestations of scabies or mange ; now we know that, as 

 respects this in its genuine manifestations, a very trifling pro- 

 portion of skin disturbances are traceable to its inroads. 



That the knowledge of this group of diseases is rather less 

 cultivated and understood than many others, is probably 

 largely owing to the fact that while the general and obvious 

 features of very many are much ahke, the separate elemental 

 lesions of these and of distinct and individual diseases are 

 liable to variation, and that for their correct diagnosis there is 

 required a somewhat close attention. 



They are certainly common enough, and as to their power 

 of inconveniencing the animal, causing much disfigurement, 

 and entailing monetary loss on owners because of their horses' 

 inability to perform ordinary work, they are highly important. 

 In their management, too, there is an inducement held out 

 for their careful study, in the fact that remedial measures 

 when beneficial are patent to all. 



As a field for the operation of morbid activities, we find that 

 elementary textural changes are here very much like similar 

 processes in other situations and textures of the body, modified 

 probably more by position and relations to the outer world 

 than by anatomical formation. 



In the history of the causation of skin diseases, although 

 agencies operating from within, either congenital or acquired, 

 may possess the power of independently developing or of in- 

 tensifying and modifying many affections when appearing, 

 there seems little doubt that the more numerous and more 

 potent factors in their production are agencies and influences 

 acting from Avithout. Thus it is that, although we may be 

 assisted in forming our diagnosis by a knowledge of the history 

 of the disturbance in the animal, and the conditions to Avhich 

 it may have been subjected, still our chief means of infor- 

 mation rests with the visible manifestations of diseases as pre- 

 sented for our observation ; and that in their treatment local 



